Approximately 252,000 hip fractures occur each year in the United States. Despite the relatively small incidence, hip fractures are responsible for approximately 3.5 million hospital days in the United States. In addition, hip fractures account for more hospital days than tibia fractures, vertebral fractures, and pelvic fractures combined. Further, hip fractures account for more than half of the total hospital admissions of all fractures and more than half of the ambulance calls for fractures.
Various types of orthopedic devices are known for the fixation of bone fragments. Such devices typically are used to stabilize bones by maintaining fractured bone portions in relatively fixed positions with respect to each other. The alignment and stability provided by the devices promotes the healing of fractures, allowing proper fusion to occur.
Internal fixation devices include bone screws, which are used in a variety of orthopedic applications for fixation of bone fragments. Bone fragments may be positioned in a desired configuration, and one or more holes may be drilled and tapped across the fracture. Compression and stabilization of the bone fragments may then be effected by screwing bone screws into the holes. One limitation associated with bone screws, however, is that repositioning or adjusting the bone screws following implantation is difficult. In order to accommodate a different alignment, it is often necessary to remove the original bone screws and drill new holes for subsequent bone screw implantation.
Metal pins also are often used to stabilize bones. Similar to bone screws, metal pins may be inserted in holes drilled across bone fragments to confer stability to the bone. However, as with bone screws, removal of the pins may be required if subsequent realignment of bone portions is necessary.
Intramedullary implants are another device used for fixation of bone fragments. Such a device may be placed in the central canal of a fractured bone and locked thereto at the longitudinal ends of the device using screws. The use of intramedullary implants is very invasive, though, and the implants are difficult to manipulate once installed within the canals of bone fragments. In the case of intertrochanteric hip fractures, intramedullary nails interlock proximally into the femoral head. However, often times, patients managed with intramedullary nailing experience increased pain and deformity, compared to patients managed with plate fixation. In addition, patients managed with intramedullary nailing often have more procedure-related complications, particularly bone fracture.
External fixation devices also are commonly used to stabilize bone segments. These devices employ a plurality of pins which extend through a patient's skin into holes drilled in fractured bone. Clamps are used to secure the pins to a common apparatus, which may, for example, take the form of a rod that is disposed generally parallel to the anatomically correct longitudinal axis of the fractured bone. The clamps in combination with the common apparatus create a rigid frame for immobilizing the fracture to promote healing.
External skeletal fixation is a preferred method of treatment for various limb deformities, injuries, and other conditions including: severe open fractures, fractures associated with severe burns, fractures requiring distraction, fractures requiring limb lengthening, arthrodesis, infected fractures, and nonunions. External fixation offers several advantages over the above-mentioned internal fixation approaches. For example, external fixation enables skeletal stabilization to be managed from a location that is generally remote from the proximity of deformity, injury, or disease, thereby permitting direct surveillance of the limb and wound during related or subsequent procedures. In addition, external fixation facilitates adjustment of fracture alignment, bone lengthening, bone compression, and fixed distraction following initial surgery. Furthermore, minimal interference with proximal and distal joints allows immediate mobilization of a wounded limb, and insertion of the fixator pins can be performed under local anesthesia.
However, external fixation is not commonly considered for the treatment of intertrochanteric femur fractures. An intertrochanteric hip fracture occurs between the greater trochanter and the lesser trochanter. Conventionally, intertrochanteric fractures are treated using an engineered metallic fixation device designed to maintain the fracture fragments in their post reduction position. Compression across the fracture site compresses the proximal and distal fragments to each other, which assists in the healing of the fracture.
The current treatment of intertrochanteric fractures is surgical intervention. Though healing rates for previous nonsurgical methods may have been acceptable, these nonsurgical methods are often accompanied by unacceptable morbidity and mortality rates due to frequent, non-orthopedic complications associated with prolonged immobilization or inactivity. The complications include the following: 1) pulmonary complications of pneumonia resulting from inactivity, 2) pulmonary emboli from deep vein thrombosis (DVT) caused by immobilization of an extremity, 3) bedsores from prolonged bed rest, 4) loss of motion of the lower extremity joints and muscle atrophy due to prolonged immobilization, and 5) union of the fracture in an unacceptable position resulting in a deformity.
Early experiences with external fixation for intertrochanteric fractures were associated with postoperative complications, such as varus collapse. However, the ability to treat intertrochanteric fractures with short operative times, minimal blood loss, and potentially with only local anesthesia have led some to advocate its use in selected patients. The patients most suitable for such treatment include those at unacceptably high risk for complications related to general or regional anesthesia. The device typically consists of one or two half pins placed into the femoral neck to within 10 millimeters of the subchondral bone. The fracture is reduced and the pins are connected through clamps and a bar to two or three half pins placed in the proximal femur.
Since the elderly population is mostly affected with intertrochanteric fractures, expedition in mobilization with less invasive surgeries, lighter anesthesia, less blood loss, and smaller incisions are desirable for the fracture fixation techniques. The future of intertrochanteric fracture repair focuses, in part, on fixation devices that are more forgiving, with retention of the fixation, regardless of whether the fracture is ideally reduced or has an element of instability.
While various surgical fixation devices are now available for the treatment of essentially all intertrochanteric fractures, the indications and contraindications of the technique must also be matched with the patient's activity level, degree of osteoporosis, and realistic expected outcome. In addition, there remains a need for fixation devices with improved adjustability. In particular, there remains a need for fixation devices with improved joints and overall constructions.
Therefore, a fracture fixation device is needed that overcomes the above limitations.